1. Field of Invention
The invention relates to an illuminating device and, in particular, to an outdoor illuminating device.
2. Related Art
ROC Pat. No. M364181 disclosed an “LED lamp and the closed cooling device thereof”. In the prior art, the LED lamp (as shown in FIG. 1) is susceptible to dusts and moisture that enter via the cooling holes of the lamp housing. They stay and accumulate inside the LED module, heat homogenizer, or heat sink fins, covering the heat-dissipating area and affecting the cooling efficiency of the LED lamp.
Therefore, the above-mentioned patent has the heat sink attached to the inner wall of the lamp housing. The surfaces of the heat sink and the lamp housing enable fast heat dissipation to increase the heat-dissipating efficiency. In comparison with the prior art, it can avoid the problem of dust accumulation on the surfaces of the heat homogenizer and the heat sink fins and thus the worse heat-dissipating efficiency.
Although the closed space formed by the lamp housing, the frame, and the heat conductive board can maintain the cleanness inside the lamp and prevent dusts and moisture from entering, the lamp housing in fact still has the problem of bad cooling due to the lack of air circulation. Once the LED module is turned on and emits light, the heat is transferred by a heat pipe to the fins, a heat conductive medium, and the lamp housing. Nevertheless, the heat is completely kept inside the lamp housing due to the closed space. The heat exchange with the environment relies completely on the lamp housing. In addition to an extremely hot lamp housing, the heat sink fins also lose their functions. In the end, the LED modules still operate under high temperature and are likely to break down.
It is a primary goal of the invention to solve the above-mentioned problem that waterproof and heat dissipation cannot be obtained at the same time in the conventional illuminating devices.